The Sea-Side Everlasting Pea (Lathyrus maritimus) is a much commoner plant of the coast, and may be readily recognised by its general resemblance to the garden sweet-pea. The genus to which it belongs is closely allied to the vetches, but may be distinguished by the style, which is flattened below the stigma, hairy on the inner or upper side, but quite smooth on the outer side. The sea-side species has an angled (but not winged) stem, from one to three feet long, compound tendrilled leaves with many oval leaflets, and large oval or cordate stipules. Its purple flowers are in bloom during July and August. A variety of this plant (acutifolius), with a slender straggling stem and narrow acute leaflets, occurs on some parts of the Scottish coast.
Fig. 301.—The Sea Stork’s-bill
The Geraniaceæ is represented at the sea-side by the Sea Stork’s-bill (Erodium maritimum), which, however, is by no means a very common flower. Its relationship to the other stork’s-bills and the crane’s-bills may be readily proved by the five persistent sepals, five distinct clawed petals, the five to ten stamens attached under the ovary (for we have now reached that division of the polypetalous exogens distinguished by this mode of insertion of the stamens), and the five carpels surrounding a long beak resembling that of the stork and the crane. The plant may sometimes be seen on sandy shores, averaging a foot in height, though very variable in this respect, and displaying its pretty pink flowers during the whole of the summer. The principal features by which it is to be distinguished from the two other British plants of the same species are its ovate or cordate leaves with very short petioles, and the presence of only one or two flowers on each peduncle.
Passing now to the Sea Mallow (Lavatera arborea), we are dealing with another rather rare plant, of the order Malvaceæ, sometimes met with on rocky coasts, chiefly, it appears, on the north coast of Cornwall and Devon. This is a very shrubby plant, as its specific name implies, and it is sometimes popularly known as the Tree Mallow on that account. It has a very woody stem, growing to a height of four or five feet, and bearing seven-pointed, downy leaves, and solitary, axillary, purple flowers. As in the other mallows, the flowers have five petals, which are curiously twisted when in the bud, five sepals, a large number of stamens united into a tube, and an ovary of many cells, but it may be distinguished from the other species of the order by its three-lobed bracts. The plant is found principally in wild, uncultivated spots, but is commonly grown as a garden plant by the cottagers of villages in the south-west, and under cultivation it frequently grows to a height of nine or ten feet, with a tree-like stem three or four inches in thickness; and it produces such a quantity of fibre that its cultivation for manufacturing purposes has been suggested.
We now come to another of the very extensive orders, at least as far as British plants are concerned, although it contains only a few sea-side species. We refer to the Caryophyllaceæ, containing the pinks, campions, catchflies, chickweeds, &c. The chief features of the order are jointed, herbaceous stems, opposite leaves, and regular white or red flowers with four or five sepals and petals, eight or ten stamens, and a capsular fruit opening at the top with teeth.
One of the commonest species we have to consider is the Sea Campion (Silene maritima), common on nearly all coasts, and often growing in small crevices of the bare rocks quite within the reach of the spray of storm-waves. In common with the other members of its genus it is characterised by a tubular calyx of united sepals, ten stamens, and a three-celled capsule opening at the top with six teeth; but it may be known at once by its small size, being only a few inches in height, and its solitary flowers with calyx much inflated and the corolla only shortly cleft.
The Sea Sand Wort (Spergularia marina) is another common plant of the coast, recognised by its slender, creeping stems; linear, stipuled, fleshy leaves, convex below and blunt at the apex; and its pinkish-white flowers. The Sea Purslane (Honckenya peploides), belonging to the same order, is also a creeping plant, with ovate, acute fleshy leaves, flowering from May to August. It is the only British plant of its genus, and may be distinguished from others by the absence of stipules, distinct sepals, petals entire, ten stamens, and from three to five styles. The flowers are white, solitary, and sessile. The one remaining species of the sea-side Caryophyllaceæ is the Sea Pearl Wort (Sagina maritima). This plant is closely allied to the last, being a creeper with exstipulate leaves and distinct sepals, but its flowers are reddish white, on erect peduncles, with very small petals. The leaves, too, are linear, fleshy, and obtuse. There are three distinct varieties of this plant, two of which have erect stems with short internodes, while the third is procumbent with long internodes; and in all three the capsules are shorter than the sepals.